The present invention relates to a method and apparatus for manufacturing articles of hydraulic substances.
Various types of methods of manufacturing articles of hydraulic substances such as cements, for example Portland cement, plasters, and calcium silicate have been proposed in the past. The method of manufacturing articles of hydraulic substances generally comprises a plurality of steps including compounding raw materials, pouring the raw materials into a mould, pretreating of the mould, surface finishing of the article and accelerating the curing of the article. Accordingly, in order to sequentially perform such plurality of process steps, it is necessary to use very large equipment installed at a large site. In modern industry, such process steps should be made in a flow system. The curing treatment or the curing acceleration treatment of the products requires at least several hours or more because hydration reaction should be suitably advanced and sludge like substance mixed with the water should be hardened to a hardness permitting removal of the hardened products from the mould. Such increases in the treatment time increases the area of the site required for the flow system. Furthermore, in order to accomplish the curing treatment in several hours it is necessary to preset particular heating and pressurizing conditions thus requiring a large installation. Although the articles of the type described above are used as structural component elements for fabricating buildings and structures and manifest high compression strength, their tensile strength is considerably smaller than metals as is well known in the art. For this reason, it is necessary to embed reinforming steel rods in the products. Moreover, for the purpose of providing for sun light and wind and for passing conduits for electric cables town gas, water and sewage water, etc., through the walls, it is usual to incorporate window frames and various pipings into the moulded articles of hydraulic substances. Further, connecting members or fixtures are also incorporated into the articles for the purpose of interconnecting them or mounting attachments thereon. For this reason, it is advantageous to mould the articles of hydraulic substances which generally take the form of flat plates, with their wider side surfaces opened. When the articles are moulded with their narrower side surfaces opened it is difficult to correctly embed such connecting members or fixtures, and in some cases it is impossible to do so. This requires a large amount of labor and processing steps. Where moulds are arranged in a flow system with their wider side surfaces opened, a large site and large equipment are required which makes installation and operation expensive. Modern factories designed for mass production of large concrete articles require sites of several thousands square meters and 30 to 40 employees or more.